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Komodo Dragon (Varanus komodoensis) Fact Sheet: Physical Characteristics

Komodo Dragon (Varanus komodoensis)

Physical Characteristics

Body measurements

AttributeMalesFemales
Weight up to 90 kg (198 lb) up to 70 kg (154 kg)
Length 3 m (10 ft) 2 m (6.6 ft)

General Appearance

Body size

  • Largest living lizard
  • Head raised to full extent is approximately 40 cm above the ground. When lowered the animal is less than 20 cm high (Long neck can stretch to give the dragon a better view of its surroundings in tall grass.
  • Males are bulkier and larger than females.
  • Juvenile Komodos are slender and agile. Adults are massive with flatter bodies and proportionately shorter tails

Traits

  • Toes have sharp, recurved claws.
  • Teeth are specialized for a carnivorous diet. They are serrated, compressed laterally, and curved posteriorly with a sharp tip and broad base, (Curved teeth are better than straight teeth for catching and holding prey). Although many varanids have one or two replacement teeth at each position, the komodo has four or five. Longest teeth are approximately 2 cm.
  • Venom toxins are now known to be present in toxin-secreting glands of monitor lizards (Fry et al. 2006; Fry et al. 2009)
    • Biologists hypothesize that venom systems evolved early in the evolution of both snakes and lizards
    • Nine toxin types are shared between lizards and snakes
    • In one monitor lizard, the Lace Monitor (Varanus varius), its toxin effects blood pressure and clotting ability of its prey
  • Short intestine is typical of carnivores (Diets high in proteins and lipids don't require a great deal of digestive processing)
  • Skin is like "chain-mail" with numerous osteoderms. Shedding occurs in patches and lasts about 6 months each year (In the Komodo this begins in September)
  • Tongue is long and narrow with a deep fork at its tip. It does not move freely in the mouth, but retracts into a sheath. It is partially supported by a complex structure of bone and cartilage called the hyoid apparatus. Varanids are unique in using their tongues only as a sensory organ for locating prey and as a socialization tool. Other lizards use the tongue to manipulate food.

Coloration

  • Most adults are uniformly gray or clay-colored. Until the age of four they have much brighter, speckled skin. (Komodos of Flores retain brighter coloration)
  • There is little sexual dimorphism. The flanks of adult females have more red than males. Yellowish-green nose spots are more common in males
  • The light yellow tongue is species specific. (V. salvator has a blue tongue, V. dumerili and V. grayi have pink tongues)

Other Physical and Physiological Characteristics

Olfaction

  • Sense of smell extremely important in food detection. Komodos can detect the scent of carrion from as far as 11 km. (Decomposition releases volatile oils - wind and size of prey are important factors)
  • Each external nostril leads to a multi-chambered nasal capsule. (One of the chambers functions to excrete excess sodium.) A pair of Jacobson's organs open into the roof of the mouth. Scent particles are collected by the forked tongue and delivered to these sense organs which stimulate the brain to react.

Vision

  • Eyes are placed laterally and covered by two unequal lids.
  • Upper lid has little mobility.
  • Lower lid contains a cartilaginous plate which slides over surface of the eye

Hearing

  • The ear is important for maintaining balance as well as sound reception.
  • Behavior seems to be more scent than sound oriented

Respiration

  •  Varanid lungs are larger than most reptiles.
  • Take in relatively larger amounts of oxygen and their physiology produces a more efficient system of air circulation.
  • Breathing rate is regular and low but varanids can voluntarily hold their breath for long periods.

Circulation

  •  Varanids have a more complex heart structure and blood chemistry than other lizards.
  • This allows them to achieve intense activity without becoming exhausted.

Water/Salt Balance

  • Water makes up 70% of a lizard's body weight. (10% more than humans).
  • Varanid skin is covered with scales and contains no sweat glands.
  • Excess sodium is removed by a special salt-secreting glands in the nasal capsules (many lizards have them)

Skin Armor

komodo dragon skin

The chain mail-like scales covering a komodo dragon's body protect it from scapes and scratches.

Image credit: © San Diego Zoo Global. All rights reserved.

Page Citations

Auffenberg (1981)
Ciofi (2004)
De Lisle (1996)
King & Green (1993)
Fry et al. (2006)
Fry et al. (2009)

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